The environmental impacts of various substances on all levels of organisms are under investigation. Among these substances, endocrine-disrupting compounds EDCs present a threat, although the environmental significance of these compounds remains largely unknown. To shed some light on this field, we assessed the effects of 17β-oestradiol on the growth, reproduction and formation of free radicals in Eisenia fetida.

Methodology-Principal Findings

Although the observed effects on growth and survival were relatively weak, a strong impact on reproduction was observed 50.70% inhibition in 100 μg-kg of E2. We further demonstrated that the exposure of the earthworm Eisenia fetida to a contaminant of emerging concern, 17β-oestradiol E2, significantly affected the molecules involved in antioxidant defence. Exposure to E2 results in the production of reactive oxygen species ROS and the stimulation of antioxidant systems metallothionein and reduced oxidized glutathione ratio but not phytochelatins at both the mRNA and translated protein levels. Matrix-assisted laser desorption-ionization MALDI-imaging revealed the subcuticular bioaccumulation of oestradiol-3,4-quinone, altering the levels of local antioxidants in a time-dependent manner.

Conclusions-Significance

The present study illustrates that although most invertebrates do not possess oestrogen receptors, these organisms can be affected by oestrogen hormones, likely reflecting free diffusion into the cellular microenvironment with subsequent degradation to molecules that undergo redox cycling, producing ROS, thereby increasing environmental contamination that also perilously affects keystone animals, forming lower trophic levels.